As the world's drug habit shows, governments are failing in their quest to monitor every London window-box and Andean hillside for banned plants. But even that Sisyphean task looks easy next to the fight against synthetic drugs. No sooner has a drug been blacklisted than chemists adjust their recipe and start churning out a subtly different one.

Any set of instructions for preparing a mixture of ingredients. [from 17th c.]

By extension, a plan or procedure to obtain a given end result. [from 17th c.]

[Isaac Newton] was obsessed with alchemy. He spent hours copying alchemical recipes and trying to replicate them in his laboratory. He believed that the Bible contained numerological codes. The truth is that Newton was very much a product of his time.

Now especially, a set of instructions for making or preparing food dishes. [from 18th c.]

A set of conditions and parameters of an industrial process to obtain a given result.